cmake(python): Add BUILD_VENV option

CMakeLists.txt

@@ -88,6 +88,10 @@ if(BUILD_SHARED_LIBS AND MSVC)
   set(CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS ON)
 endif()
 
+# Disable CTest targets
+set_property(GLOBAL PROPERTY CTEST_TARGETS_ADDED 1)
+include(CTest)
+
 # By default only build the C++ library.
 option(BUILD_CXX "Build C++ library" ON)
 message(STATUS "Build C++ library: ${BUILD_CXX}")
@@ -286,6 +290,10 @@ if(BUILD_PYTHON)
     "NOT BUILD_DEPS" ON)
   message(STATUS "Python: Build pybind11: ${BUILD_pybind11}")
 
+  CMAKE_DEPENDENT_OPTION(BUILD_VENV "Create Python venv in BINARY_DIR/python/venv" OFF
+    "NOT BUILD_TESTING" ON)
+  message(STATUS "Python: Create venv: ${BUILD_VENV}")
+
   option(VENV_USE_SYSTEM_SITE_PACKAGES "Python venv can use system site packages" OFF)
   message(STATUS "Python: Allow venv to use system site packages: ${VENV_USE_SYSTEM_SITE_PACKAGES}")
 
@@ -297,10 +305,6 @@ endif()
 add_subdirectory(cmake/dependencies dependencies)
 list(APPEND CMAKE_PREFIX_PATH ${CMAKE_CURRENT_BINARY_DIR}/dependencies/install)
 
-# Disable CTest targets
-set_property(GLOBAL PROPERTY CTEST_TARGETS_ADDED 1)
-include(CTest)
-
 # Basic type
 include(CMakePushCheckState)
 cmake_push_check_state(RESET)

cmake/python.cmake

@@ -179,7 +179,7 @@ add_custom_target(Py${PROJECT_NAME}_proto
 ###################
 ##  Python Test  ##
 ###################
-if(BUILD_TESTING)
+if(BUILD_VENV)
   search_python_module(NAME virtualenv PACKAGE virtualenv)
   # venv not working on github runners
   # search_python_internal_module(NAME venv)
@@ -192,7 +192,9 @@ if(BUILD_TESTING)
   else()
     set(VENV_Python3_EXECUTABLE ${VENV_DIR}/bin/python)
   endif()
+endif()
 
+if(BUILD_TESTING)
   # add_python_test()
   # CMake function to generate and build python test.
   # Parameters:
@@ -371,7 +373,7 @@ configure_file(
   @ONLY)
 install(SCRIPT ${PROJECT_BINARY_DIR}/python/python-install.cmake)
 
-if(BUILD_TESTING)
+if(BUILD_VENV)
   # make a virtualenv to install our python package in it
   add_custom_command(TARGET python_package POST_BUILD
     # Clean previous install otherwise pip install may do nothing
@@ -390,7 +392,9 @@ if(BUILD_TESTING)
     WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
     COMMENT "Create venv and install ${PYTHON_PROJECT}"
     VERBATIM)
+endif()
 
+if(BUILD_TESTING)
   configure_file(
     ${PROJECT_SOURCE_DIR}/ortools/init/python/version_test.py.in
     ${PROJECT_BINARY_DIR}/python/version_test.py